Class SerialBlob

  • All Implemented Interfaces:
    Serializable, Cloneable, Blob

    public class SerialBlob
    extends Object
    implements Blob, Serializable, Cloneable
    A serialized mapping in the Java programming language of an SQL BLOB value.

    The SerialBlob class provides a constructor for creating an instance from a Blob object. Note that the Blob object should have brought the SQL BLOB value's data over to the client before a SerialBlob object is constructed from it. The data of an SQL BLOB value can be materialized on the client as an array of bytes (using the method Blob.getBytes) or as a stream of uninterpreted bytes (using the method Blob.getBinaryStream).

    SerialBlob methods make it possible to make a copy of a SerialBlob object as an array of bytes or as a stream. They also make it possible to locate a given pattern of bytes or a Blob object within a SerialBlob object and to update or truncate a Blob object.

    Thread safety

    A SerialBlob is not safe for use by multiple concurrent threads. If a SerialBlob is to be used by more than one thread then access to the SerialBlob should be controlled by appropriate synchronization.

    Since:
    1.5
    See Also:
    Serialized Form
    • Constructor Summary

      Constructors 
      Constructor Description
      SerialBlob​(byte[] b)
      Constructs a SerialBlob object that is a serialized version of the given byte array.
      SerialBlob​(Blob blob)
      Constructs a SerialBlob object that is a serialized version of the given Blob object.
    • Method Summary

      Modifier and Type Method Description
      Object clone()
      Returns a clone of this SerialBlob.
      boolean equals​(Object obj)
      Compares this SerialBlob to the specified object.
      void free()
      This method frees the SerialBlob object and releases the resources that it holds.
      InputStream getBinaryStream()
      Returns this SerialBlob object as an input stream.
      InputStream getBinaryStream​(long pos, long length)
      Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.
      byte[] getBytes​(long pos, int length)
      Copies the specified number of bytes, starting at the given position, from this SerialBlob object to another array of bytes.
      int hashCode()
      Returns a hash code for this SerialBlob.
      long length()
      Retrieves the number of bytes in this SerialBlob object's array of bytes.
      long position​(byte[] pattern, long start)
      Returns the position in this SerialBlob object where the given pattern of bytes begins, starting the search at the specified position.
      long position​(Blob pattern, long start)
      Returns the position in this SerialBlob object where the given Blob object begins, starting the search at the specified position.
      OutputStream setBinaryStream​(long pos)
      Retrieves a stream that can be used to write to the BLOB value that this Blob object represents.
      int setBytes​(long pos, byte[] bytes)
      Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.
      int setBytes​(long pos, byte[] bytes, int offset, int length)
      Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
      void truncate​(long length)
      Truncates the BLOB value that this Blob object represents to be len bytes in length.
    • Constructor Detail

      • SerialBlob

        public SerialBlob​(byte[] b)
                   throws SerialException,
                          SQLException
        Constructs a SerialBlob object that is a serialized version of the given byte array.

        The new SerialBlob object is initialized with the data from the byte array, thus allowing disconnected RowSet objects to establish serialized Blob objects without touching the data source.

        Parameters:
        b - the byte array containing the data for the Blob object to be serialized
        Throws:
        SerialException - if an error occurs during serialization
        SQLException - if a SQL errors occurs
      • SerialBlob

        public SerialBlob​(Blob blob)
                   throws SerialException,
                          SQLException
        Constructs a SerialBlob object that is a serialized version of the given Blob object.

        The new SerialBlob object is initialized with the data from the Blob object; therefore, the Blob object should have previously brought the SQL BLOB value's data over to the client from the database. Otherwise, the new SerialBlob object will contain no data.

        Parameters:
        blob - the Blob object from which this SerialBlob object is to be constructed; cannot be null.
        Throws:
        SerialException - if an error occurs during serialization
        SQLException - if the Blob passed to this to this constructor is a null.
        See Also:
        Blob
    • Method Detail

      • getBytes

        public byte[] getBytes​(long pos,
                               int length)
                        throws SerialException
        Copies the specified number of bytes, starting at the given position, from this SerialBlob object to another array of bytes.

        Note that if the given number of bytes to be copied is larger than the length of this SerialBlob object's array of bytes, the given number will be shortened to the array's length.

        Specified by:
        getBytes in interface Blob
        Parameters:
        pos - the ordinal position of the first byte in this SerialBlob object to be copied; numbering starts at 1; must not be less than 1 and must be less than or equal to the length of this SerialBlob object
        length - the number of bytes to be copied
        Returns:
        an array of bytes that is a copy of a region of this SerialBlob object, starting at the given position and containing the given number of consecutive bytes
        Throws:
        SerialException - if the given starting position is out of bounds; if free had previously been called on this object
        See Also:
        Blob.setBytes(long, byte[])
      • length

        public long length()
                    throws SerialException
        Retrieves the number of bytes in this SerialBlob object's array of bytes.
        Specified by:
        length in interface Blob
        Returns:
        a long indicating the length in bytes of this SerialBlob object's array of bytes
        Throws:
        SerialException - if an error occurs; if free had previously been called on this object
      • getBinaryStream

        public InputStream getBinaryStream()
                                    throws SerialException
        Returns this SerialBlob object as an input stream. Unlike the related method, setBinaryStream, a stream is produced regardless of whether the SerialBlob was created with a Blob object or a byte array.
        Specified by:
        getBinaryStream in interface Blob
        Returns:
        a java.io.InputStream object that contains this SerialBlob object's array of bytes
        Throws:
        SerialException - if an error occurs; if free had previously been called on this object
        See Also:
        setBinaryStream(long)
      • position

        public long position​(byte[] pattern,
                             long start)
                      throws SerialException,
                             SQLException
        Returns the position in this SerialBlob object where the given pattern of bytes begins, starting the search at the specified position.
        Specified by:
        position in interface Blob
        Parameters:
        pattern - the pattern of bytes for which to search
        start - the position of the byte in this SerialBlob object from which to begin the search; the first position is 1; must not be less than 1 nor greater than the length of this SerialBlob object
        Returns:
        the position in this SerialBlob object where the given pattern begins, starting at the specified position; -1 if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at 1
        Throws:
        SerialException - if an error occurs when serializing the blob; if free had previously been called on this object
        SQLException - if there is an error accessing the BLOB value from the database
      • position

        public long position​(Blob pattern,
                             long start)
                      throws SerialException,
                             SQLException
        Returns the position in this SerialBlob object where the given Blob object begins, starting the search at the specified position.
        Specified by:
        position in interface Blob
        Parameters:
        pattern - the Blob object for which to search;
        start - the position of the byte in this SerialBlob object from which to begin the search; the first position is 1; must not be less than 1 nor greater than the length of this SerialBlob object
        Returns:
        the position in this SerialBlob object where the given Blob object begins, starting at the specified position; -1 if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at 1
        Throws:
        SerialException - if an error occurs when serializing the blob; if free had previously been called on this object
        SQLException - if there is an error accessing the BLOB value from the database
      • setBytes

        public int setBytes​(long pos,
                            byte[] bytes)
                     throws SerialException,
                            SQLException
        Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.
        Specified by:
        setBytes in interface Blob
        Parameters:
        pos - the position in the SQL BLOB value at which to start writing. The first position is 1; must not be less than 1 nor greater than the length of this SerialBlob object.
        bytes - the array of bytes to be written to the BLOB value that this Blob object represents
        Returns:
        the number of bytes written
        Throws:
        SerialException - if there is an error accessing the BLOB value; or if an invalid position is set; if an invalid offset value is set; if free had previously been called on this object
        SQLException - if there is an error accessing the BLOB value from the database
        See Also:
        getBytes(long, int)
      • setBytes

        public int setBytes​(long pos,
                            byte[] bytes,
                            int offset,
                            int length)
                     throws SerialException,
                            SQLException
        Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written. Writing starts at position pos in the BLOB value; len bytes from the given byte array are written.
        Specified by:
        setBytes in interface Blob
        Parameters:
        pos - the position in the BLOB object at which to start writing. The first position is 1; must not be less than 1 nor greater than the length of this SerialBlob object.
        bytes - the array of bytes to be written to the BLOB value
        offset - the offset in the byte array at which to start reading the bytes. The first offset position is 0; must not be less than 0 nor greater than the length of the byte array
        length - the number of bytes to be written to the BLOB value from the array of bytes bytes.
        Returns:
        the number of bytes written
        Throws:
        SerialException - if there is an error accessing the BLOB value; if an invalid position is set; if an invalid offset value is set; if number of bytes to be written is greater than the SerialBlob length; or the combined values of the length and offset is greater than the Blob buffer; if free had previously been called on this object
        SQLException - if there is an error accessing the BLOB value from the database.
        See Also:
        getBytes(long, int)
      • setBinaryStream

        public OutputStream setBinaryStream​(long pos)
                                     throws SerialException,
                                            SQLException
        Retrieves a stream that can be used to write to the BLOB value that this Blob object represents. The stream begins at position pos. This method forwards the setBinaryStream() call to the underlying Blob in the event that this SerialBlob object is instantiated with a Blob. If this SerialBlob is instantiated with a byte array, a SerialException is thrown.
        Specified by:
        setBinaryStream in interface Blob
        Parameters:
        pos - the position in the BLOB value at which to start writing
        Returns:
        a java.io.OutputStream object to which data can be written
        Throws:
        SQLException - if there is an error accessing the BLOB value
        SerialException - if the SerialBlob in not instantiated with a Blob object that supports setBinaryStream(); if free had previously been called on this object
        See Also:
        getBinaryStream()
      • truncate

        public void truncate​(long length)
                      throws SerialException
        Truncates the BLOB value that this Blob object represents to be len bytes in length.
        Specified by:
        truncate in interface Blob
        Parameters:
        length - the length, in bytes, to which the BLOB value that this Blob object represents should be truncated
        Throws:
        SerialException - if there is an error accessing the Blob value; or the length to truncate is greater that the SerialBlob length; if free had previously been called on this object
      • getBinaryStream

        public InputStream getBinaryStream​(long pos,
                                           long length)
                                    throws SQLException
        Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.
        Specified by:
        getBinaryStream in interface Blob
        Parameters:
        pos - the offset to the first byte of the partial value to be retrieved. The first byte in the Blob is at position 1
        length - the length in bytes of the partial value to be retrieved
        Returns:
        InputStream through which the partial Blob value can be read.
        Throws:
        SQLException - if pos is less than 1 or if pos is greater than the number of bytes in the Blob or if pos + length is greater than the number of bytes in the Blob
        SerialException - if the free method had been previously called on this object
        Since:
        1.6
      • free

        public void free()
                  throws SQLException
        This method frees the SerialBlob object and releases the resources that it holds. The object is invalid once the free method is called.

        If free is called multiple times, the subsequent calls to free are treated as a no-op.

        Specified by:
        free in interface Blob
        Throws:
        SQLException - if an error occurs releasing the Blob's resources
        Since:
        1.6
      • equals

        public boolean equals​(Object obj)
        Compares this SerialBlob to the specified object. The result is true if and only if the argument is not null and is a SerialBlob object that represents the same sequence of bytes as this object.
        Overrides:
        equals in class Object
        Parameters:
        obj - The object to compare this SerialBlob against
        Returns:
        true if the given object represents a SerialBlob equivalent to this SerialBlob, false otherwise
        See Also:
        Object.hashCode(), HashMap
      • clone

        public Object clone()
        Returns a clone of this SerialBlob. The copy will contain a reference to a clone of the internal byte array, not a reference to the original internal byte array of this SerialBlob object. The underlying Blob object will be set to null.
        Overrides:
        clone in class Object
        Returns:
        a clone of this SerialBlob
        See Also:
        Cloneable